Catch some Zzz’s, Lose the Pounds

March 3-10, 2013 is National Sleep Awareness Week™.  Most of us are aware of the importance of adequate and effective sleep to health and overall well-being.  Lack of sleep or poor sleep quality can make you tired and sluggish, but did you know that it can also lead to body fat accumulation?  Some recent research suggests that sleep deprivation can be as important a factor in weight gain as calorie over-consumption.

Sleep’s influence on weight gain and difficulty losing excess body fat is attributable, at least in part, to the hormones melatonin, growth hormone, and cortisol.

Melatonin and growth hormone are important hormonal modulators of energy metabolism and tissue rejuvenation that are released during sleep.  Melatonin is stimulated by darkness and inhibited by light, preparing us for sleep.  Growth hormone is responsible for increasing muscle mass, increasing fat mobilization, and decreasing fat deposition, leading to an overall decrease in body fat.  Poor sleep, either in quantity or quality, will decrease the production of melatonin and growth hormone, causing unwanted changes in our body composition.

Cortisol is our body’s stimulatory “stress hormone”.  Temporary elevations in cortisol are normal and essential to a properly functioning immune system.  However, chronically elevated cortisol levels can wreak havoc on our metabolism.

With poor or inadequate sleep, levels of melatonin and growth hormone decrease, while the production cortisol increases inversely.  Herein lies the problem:  Cortisol is another important regulator of energy metabolism and muscle maintenance, and when levels are too high, it can contribute to several factors that can allow surplus body fat to accumulate.

First, elevated cortisol increases appetite, especially cravings for refined carbohydrates (think breads, pastas, pastries, desserts, etc.).  A ravenous need for carbohydrates develops despite ample food intake and weight gain ensues.  Second, increased cortisol levels raise our blood glucose levels and make our body tissues less responsive to insulin, the hormone that acts as our signal to store unused energy as fat, particularly around the midsection (think diabetes).  Just one night of missed sleep can actually make you as insulin resistant as a type 2 diabetic.  Lastly, cortisol promotes the breakdown of skeletal muscle for energy rather than stored body fat (think muscle-wasting).

Cortisol is generally higher in the morning to get us up and at ‘em, and lower in the evening to allow us to sleep.  Sleep deprivation can cause a stage of burnout in which cortisol is rock-bottom in the morning and high in the evening.  If you’ve ever wished that you were as tired at night as you were in the morning, you may know what this feels like.

Quantity and Quality

So how much sleep is enough?

Most adults require eight to nine hours of sleep for optimal physiological rest. Some research suggests nine hours is the perfect amount for slowing the aging process, for recuperation from stress, and for complete rejuvenation.

The quality of your sleep carries just as much significance as the duration.  For optimum sleep quality, many texts say that your bedroom must be completely dark when you sleep due to the fact that your body’s red blood cells are able to register light.  Even the slightest amount light from your alarm clock or a blinking cell phone can block melatonin and growth hormone production enough to keep you out of the deepest, most restful stages of sleep.

Secrets to super sleep:

Tara Parr, MPAS, PA-C